In recent years, the reduction of carbon dioxide emissions has been sincerely desired for the purpose of environmental protection. The automotive industry has a growing expectation on the introduction of electric vehicles (EV) and hybrid electric vehicles (HEV) for the reduction of carbon oxide emissions and has increasingly developed motor-drive batteries, which become key to the practical application of these electric vehicles. Among various batteries for automotive uses, attentions are being given to bipolar batteries. The bipolar battery exhibits a high battery voltage as the flow of electric current through a current collector in a vertical direction (an electrode layer lamination direction) in the bipolar battery leads to short electron conduction passage and high output.
The bipolar battery has a collector as a structural part on both sides of which positive and negative electrode material layers are formed. Patent Document 1 teaches a collector containing a resin material for weight reduction.